InvokeModel call over cross-region

Hi s_hiruta,

I am able to reproduce the error you are facing. I did the below testing with a role that has access to all bedrock API calls.

1. Step function in Tokyo and Bedrock Model in us-east-1: I received the same error as you are getting.

2. Step function and Bedrock model in us-east-1: The step function was able to successfully perform the InvokeModel operation.

Also, if you check the article [1] under “How to get started with Amazon Bedrock and AWS Step Functions” section it specifically mentions that “Before getting started, ensure that you create the state machine in a Region where Amazon Bedrock is available. For this example, use US East (N. Virginia), us-east-1.”

3. One more observation is that in Step Function Bedrock model identifier selection lists only the models available in that specific region. In the below example only the models from ap-northeast-1 are listed by default.

So, it looks like step function can only call the InvokeModel API call in the same region where Amazon Bedrock is available.

Article links: [1] https://aws.amazon.com/blogs/aws/build-generative-ai-apps-using-aws-step-functions-and-amazon-bedrock/?trk=f3da5d15-8262-4ccc-b6ac-edb58d9955e7&sc_channel=el

Hope this helps.